Targeting the MONO Runtime causes Xamarin Build to fail

Question

After creating a simple .NET console application in Xamarin Studio, I can build/debug fine if the default Target Runtime is set to 'Microsoft .NET'.

If I set the runtime to MONO ('Mono 4.0.1'), then my project no longer builds.

The error is:

Error: Unknown MSBuild failure. Please try building the project again

The build output window shows everything succeeding up until the last line, which displays Build: 1 error, 0 warnings":

Is targeting the MONO Runtime in this way not valid? A related question here indicates that it is...

What am I doing wrong?

Running Windows7 (64 bit), Xamarin Studio 5.9. Mono 4.0.1, .NET 4.5

The build output is as follows:

Cleaning Solution: XamarinTest (Debug)

Cleaning: XamarinTest (Debug)

Build started 05/08/2015 16:57:03. __________________________________________________ Project "C:\Development\Test\XamarinTest\XamarinTest\XamarinTest.csproj" (Clean target(s)): Target CoreClean: Deleting file 'C:\Development\Test\XamarinTest\XamarinTest\obj\Debug.NETFramework,Version=v4.5.AssemblyAttribute.cs' Deleting file 'C:\Development\Test\XamarinTest\XamarinTest\bin\Debug\XamarinTest.dll.mdb' Deleting file 'C:\Development\Test\XamarinTest\XamarinTest\bin\Debug\XamarinTest.dll' Deleting file 'C:\Development\Test\XamarinTest\XamarinTest\obj\Debug\XamarinTest.dll' Deleting file 'C:\Development\Test\XamarinTest\XamarinTest\obj\Debug\XamarinTest.dll.mdb' Deleting file 'C:\Development\Test\XamarinTest\XamarinTest\obj\Debug\XamarinTest.csproj.FilesWrittenAbsolute.txt' Done building project "C:\Development\Test\XamarinTest\XamarinTest\XamarinTest.csproj".

Build succeeded. 0 Error(s) 0 Warning(s)

Time Elapsed 00:00:00.1350135

Cleaning: XamConsole (Debug)

Build started 05/08/2015 16:57:04. __________________________________________________ Project "C:\Development\Test\XamarinTest\XamConsole\XamConsole.csproj" (Clean target(s)): Target CoreClean: Deleting file 'C:\Development\Test\XamarinTest\XamConsole\obj\Debug\XamConsole.exe' Done building project "C:\Development\Test\XamarinTest\XamConsole\XamConsole.csproj".

Build succeeded. 0 Warning(s) 0 Error(s)

Time Elapsed 00:00:00.0170017

Building Solution: XamarinTest (Debug)

Building: XamarinTest (Debug)

Build started 05/08/2015 16:57:04. __________________________________________________ Project "C:\Development\Test\XamarinTest\XamarinTest\XamarinTest.csproj" (Build target(s)): Target PrepareForBuild: Configuration: Debug Platform: AnyCPU Target GenerateSatelliteAssemblies: No input files were specified for target GenerateSatelliteAssemblies, skipping. Target CoreCompile: Tool C:\Program Files (x86)\Mono\lib\mono\4.5\mcs.exe execution started with arguments: /noconfig /debug:full /debug+ /optimize- /out:obj\Debug\XamarinTest.dll MyClass.cs Properties\AssemblyInfo.cs obj\Debug.NETFramework,Version=v4.5.AssemblyAttribute.cs /target:library /define:DEBUG /nostdlib /reference:"C:\Program Files (x86)\Mono\lib\mono\4.5..\xbuild-frameworks.NETFramework\v4.5\RedistList........\4.5\System.dll" /reference:"C:\Program Files (x86)\Mono\lib\mono\4.5..\xbuild-frameworks.NETFramework\v4.5\RedistList........\4.5\System.Core.dll" /reference:"C:\Program Files (x86)\Mono\lib\mono\4.5\mscorlib.dll" /warn:4 Target DeployOutputFiles: Copying file from 'C:\Development\Test\XamarinTest\XamarinTest\obj\Debug\XamarinTest.dll.mdb' to 'C:\Development\Test\XamarinTest\XamarinTest\bin\Debug\XamarinTest.dll.mdb' Copying file from 'C:\Development\Test\XamarinTest\XamarinTest\obj\Debug\XamarinTest.dll' to 'C:\Development\Test\XamarinTest\XamarinTest\bin\Debug\XamarinTest.dll' Done building project "C:\Development\Test\XamarinTest\XamarinTest\XamarinTest.csproj".

Build succeeded. 0 Warning(s) 0 Error(s)

Time Elapsed 00:00:08.6528652

---------------------- Done ----------------------

Build: 1 error, 0 warnings

Answer 1

Workaround: Uncheck the "Use MSBUild build engine" checkbox. ( Project property => Build => General => Build engine"

It will work.